Opeth "damnation"

Maybe in the wrong category (forgive me for that) but i was just wondering, could anybody possibly help me out here. I bought opeth's damnation album the other day just out of sheer chance and i happened to like the whole progressive rock element that it has, so could you guys recommend any other albums that have this same kind of sound or feel.

2 great progressive bands that I'm into right now are Dream Theater and Tool. Of course, both are quite a bit heavier than Opeth's "Damnation", but they still have that awesome progressive style which I love. Try buying Images and Words or Scenes From a Memory by Dream Theater (their best albums btw)... not only will you most likely like them due to the fact that you're into progressive music, but you'll probably also be blown away by each of the musicians' skills.